Rules for adjustment and firing
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The first
Bulgarian instructions for the artillery fire were the Rules for artillery adjustment and fire, the so-called “Red booklet”,
introduced in 1889 by the Artillery Inspector lt.col. Petar Tantilov,
adapting the Russian Rules for firing
for field batteries (Правила
стрельбы
для полевой
батареи), proposed
two years before by the Russian general major Vladimir Nikolaevich Shklarevich.
This first Bulgarian handbook followed strictly the doctrines of the The “Red
booklet” was completed with the Hand-tables
for the firing data (Наръчни
таблици за
даните на
стрелба), elaborated on the basis
of the data furnished by the factory. These firing tables included the angle of
elevation and the lateral deviation for every range from All the rules
and the directives were addressed to the battery, which was regarded as the
basic unit of artillery. Being composed by 4 two-guns sections, it could be
employed both as a whole, and subdivided into sub-units, acting by
half-batteries, sections and, exceptionally, also single guns. No direction
was anticipated for the employ of the greater units, like the artillery
division or the regiment. The first instructions for the employ of a group of
batteries were published only two years later, in 1891. The Rules included the following chapters
: a)
Features of the projectiles. b)
General rules for firing. c)
Preparatory fire. d)
Adjustment and fire at close range. e)
Adjustment when it is difficult to distinguish the
rounds over the target from the short rounds. f)
Firing at moving targets. g)
Scale fire. h)
Firing at targets unseen by the aimer. i)
Shelling targets sheltered in dugouts and
earthworks. j)
Accountancy. k)
Tasks of the protective and observation lines. The projectiles. The first chapter
described in detail the main features and the effects of the various kinds of
projectiles, employed at that time by the Bulgarian artillery. Great
importance was deserved to the impact of an inaccurate determination of the
height of sight on the accuracy of the fire. The common shell
(граната), acting both by the burst
of the charge and by the striking energy of its splinters, could be employed
against all the targets that should appear in a field battle, both animate
and inanimate. It was equipped with percussion fuze, working
on impact. Its effect depended on the character of the ground and on the distance
of the target. Unlike the principal European regulations, that recommended to
employ it only at a distance not greater than The shrapnel (шрапнел) was equipped with a fuze that enabled to set with precision the rate
of burning. It burst into the air, before having hit the ground, and spread
the bullets on the target. The effect of the bullets on animate targets
depended upon their striking energy and their sectional density, those of
smaller diameter having the greater penetration. The main problem was to know
the point of burst that was determined by the interval of burst (the
horizontal distance between the point of burst and the target), and the
height of burst (the vertical distance of the point of burst above the
horizon). The closer the point of burst was to the target, the greater was
the velocity and, consequently, the effect of the bullets. The normal
interval was set at The case shot
(картеч) was a cylindrical zinc
case filled with round balls and was employed only
against
animate targets at close ranges (400 – The sharoha
(шароха) was a cylindrical cast iron
shell, whose head was a ball that continued to roll after the burst of the
proper shell, hitting the troops placed behind the front line. It was
regarded as ineffective already during the Russo-Turkish (1877-78) and in Generalities. Besides the general rules
for firing, the description of the individual duties in the service of the
piece and the direction about the correct manner to bring the gun into
position, the “Red booklet” dealt at length with the care of ammunition and
artillery materiel. It was a matter of the highest importance their correct
storage and maintenance, since their working order greatly affected the
accuracy of fire. In order that all the
parts worked easily and without unnecessary wear, the materiel should be kept
properly lubricated, assuring the constant maintenance of a thin film of the
proper lubricant between all working and bearing surfaces and the surfaces on
which they work or bear. Special attention should be paid to the
breech-block, whose mechanism should always work perfectly to avoid severe
accidents. Preliminary
fire
(подготвителна
стрелба) was used to provide the
recruits with a little knowledge of the firing theory, showing them how the
fall of the projectiles depended upon the height of the sight and other
adverse conditions, like the battering charge, a wrong measurement,
inadequate maintenance of the materiel and so on. Fire for adjustment (пристрелка). The purpose of the adjustment in elevation (определение
на мерника) was to find
the distance (height of sight) up to the target as quickly and accurately as
possible, according with the real situation and the features of the
projectile employed. The most probable distance was at the middle of the
bracket obtained firing a shot in front and another behind the target
(нулева
вилка = straddle). Accurate though the
adjustment might be, a margin of error would be always, owing to the
dispersion of the shots and other accidental factors. The probable error was
reduced according with the law of
probability, by lowering down the bracket and by the repetition of the
same observation. The ranging fire could be effected in three
different ways : – directly with shell : it was employed
against targets standing immobile into the open, usually starting with a
bracket not lower than 8 and not higher than 16 graduations. If the first round was
short, the range was increased; if over, it was decreased; and rounds were fired
successively increased or decreased in range until the target was bracketed.
Then the size of the bracket was successively reduced by halving the last
bracket obtained to 2 graduations for a range up to The
final limit of the bracket was repeated with another shot, to find the most
probable height of the sight, and : a)
if the straddle was obtained, the other limit of the
bracket was not repeated and the fire continued without changing the height of
sight : low bracket at 50-52 graduations, repeating the short limit (50) and
obtaining − +, the most probable
height of the sight was at 52, or repeating the large limit (52) and
obtaining − +, the most probable height the of sight was at 52; b)
if it was like the first observation, the other
limit of the low bracket was repeated and if this time the straddle was
obtained, the fire continued without changing the height of sight : low
bracket at 50-52 graduations, repeating the short limit (50) and obtaining −
−, the large limit (52) was repeated and obtaining + −, the most
probable height of the sight was at 52 (beginning with the large limit the
process was the same); c)
if the straddle was not obtained even at the other
limit, the fire was directed at the middle of the low bracket : low bracket
at 50-52 graduations, repeating the short limit (50) and obtaining − −,
and the large limit (52) and obtaining + +, the most probable height of the
sight was at 51. The
most probable height of the sight should be verified firing a group of four
shots. When some of the rounds were short and some over the targets owing to
the dispersion of the shells, and not by an error in aiming the gun or by
accident, the adjustment was regarded as finished and the guns shifted to fire
for effect. The “Red booklet” listed five
different cases that might occur during the ranging fire, showing what
the battery commander had to do in each of them. – with shell and shifting to shrapnel : at first the
adjustment was made with shell, exactly as above, but after having fired the
group of 4 shots, one or two sections shifted to shrapnel fire. The height of
the sight for them was 1 or 2 graduations lower than the height that with
shells had obtained less short rounds or the same number of rounds short and
over the target. In the meantime the sections charged with shells fired for
effect and filled in the pauses, until the burning time of the fuze had been
set. Then the whole battery shifted to shrapnel fire, adopting the height of
the sight that had obtained the greater number of short rounds : if the
number of the rounds short and over was the same, the height was narrowed by
1 graduation. In either case the fuze was set for a normal burst. To control
the interval of burst, one section fired a verifying salvo, changing the
elevation by 2 graduations. If no round fell over the target, the elevation
was changed again by 2 graduations. When one or more rounds fell over, the
guns kept the long limit of the bracket or narrowed the elevation of the
verifying salvo by 1 graduation. – directly with shrapnel : it was regarded as
exceptional, since it required low bursts, that might result in a lot of
graze bursts, that were not only absolutely ineffective, but also of little
value for the observation. It was made by section (two guns) exactly as with
shell, excepting that in this case two observations
were made for every height of the sight. The bracket could be reduced up to 2
graduations also by means of a single observation, if the other was
lost, but the repetition of the limits and the groups should always result
from the correct number of the observations, even if it caused a great waste
of ammunition. After having fired the group of verifying shots, the whole
battery shifted to shrapnel fire simultaneously. If the number of the rounds
of the group over the target was less or equal to the number of the short
ones, the height of the sight was kept unchanged or narrowed by 1 graduation.
The interval of burst was verified as above, with fuze set at low burst to
facilitate the observation. Shifting to fire for effect, the burning of the
fuze was shortened by 0.1-0.2 seconds, but the trajectory should never be
raised. The adjustment in direction (определение
на отклонението) was required to overcome the effect of wind and
drift. In this case the sections commanders made the changes in deflection
according with the firing tables and taking into account the slope of the
axis of the guns and the direction and power of the wind. With cross wind the
correction was made by the battery commander. The deviation was regarded as
correct when the deflections of the shots on the right and on the left were
almost the same. The adjustment in height of burst (определение
на височината на пръскане) was made observing a group of shrapnel shots having the same fuze
setting. The height was regarded normal when : – at close range
not less than half of the burst were low, and no burst were on graze; – at medium
range at least one burst of every salvo was low, and not more than one burst
every two salvos was on graze; – at long range
there was no low burst in a salvo, and only one burst at most every battery
salvo was on graze. |